Most current Wi-Fi or WLAN deployments are totally separate from mobile networks, and can be seen as non-integrated from the user equipment, UE, perspective. Most operating systems, OSs, for UEs such as Android™ and ioS®, support a simple Wi-Fi offloading mechanism where a UE immediately switches all its IP traffic to a Wi-Fi network upon a detection of a suitable network with a received signal strength above a certain level. Henceforth, the decision to offload to a Wi-Fi or not is referred to as access selection strategy and the term “Wi-Fi-if-coverage” is used to refer to the aforementioned strategy of selecting Wi-Fi whenever such a network is detected.
There are several drawbacks of the “W-Fi-if-coverage” strategy illustrated in FIG. 1. FIG. 1 illustrates examples of problems in FIGS. 1a)-1d) with “Wi-Fi-if-coverage” access network selection. Wi-Fi access selection today is performed by the UE with little consideration of radio performance, session/service continuity, load, mobility, etc.
Though the user/UE can save previous pass codes for already accessed Wi-Fi Access Points, APs, hotspot login for previously non-accessed APs usually requires user intervention, either by entering the pass code in Wi-Fi Connection Manager, CM, or using a web interface. The connection manager is software on a UE that is in charge of managing the network connections of the device, taking into account user preferences, operator preferences, network conditions, etc.
In FIGS. 1a-1d, a user equipment 10 has the possibility to connect to an AP of a mobile access network 20 or an AP of a Wi-Fi Access network 30. The mobile access network 20 may operate according to the 3GPP and/or LTE standards.
In FIG. 1a, is also illustrated that the mobile access network is connected to the Internet 60 via a backhaul network 40 and the Wi-Fi access network is connected to the Internet via a backhaul network 50. The backhaul network 40 of the mobile access network may in this example provide a high rate fibre connection. The Wi-Fi access network offers an low rate xDSL connection 50. e.g. 10/2 Mbps.
The UE may connect to the AP of either the mobile access network 20 via a connection 25 offering 50 Mbps bandwidth, or the AP of the Wi-Fi access network 30 via a connection 35 offering a rate of 2 Mbps.
No consideration of expected user experience is made except those considered in the UE 10 implemented proprietary solution, and this can lead to a UE 10 being handed over from a high data rate mobile network connection 25 to a low data rate Wi-Fi connection 35. Even though the UE's OS or some high level software is smart enough to make the offload decisions only when the signal level on the Wi-Fi connection 35 is considerably better than the mobile network link 25, there can still be limitations on the backhaul 40 of the Wi-Fi AP 30 that may end up being the bottleneck.
FIG. 1b illustrates the situation when no consideration of the load conditions in the mobile network 20 and Wi-Fi network 30 are made. As illustrated, while the capacity of the Wi-Fi network 30 is full, the mobile network 20 has low load and a lot of free capacity. As such, the UE might still be offloaded to a Wi-Fi AP that is serving several UEs while the mobile network (e.g. LTE) that it was previously connected to is rather unloaded.
FIG. 1c illustrates the situation when interruptions of on-going services have occurred due to the change of IP address when the UE switches to the Wi-Fi network 30. For example, a user who started a Voice over IP (VoIP) call while connected to a mobile network 20 is likely to experience a call drop when arriving home and the UE switching to the Wi-Fi network automatically. Though some applications are smart enough to handle this and survive the IP address change (e.g. Spotify®), the majority of current applications do not. This places a lot of burden on application developers if they have to ensure service continuity.
FIG. 1d illustrates the situation when no consideration of the UE's 10 mobility along a path 15 is made. The dotted line of the oval area is indicating the coverage of the 3GPP/LTE mobile network 20, the dotted lines of the circles indicate the coverage areas of local Wi-Fi network APs 30. Due to this, a fast moving UE 10 can end up being offloaded to a Wi-Fi AP 30 for a short duration, just to be handed over back to the mobile network 20. This is specially a problem in scenarios like cafes with open Wi-Fi, where a user walking by or even driving by the cafe might be affected by this. Such ping pong between the Wi-Fi and mobile network can cause service interruptions as well as generate considerable unnecessary signalling (e.g. towards authentication servers)
Recently, Wi-Fi has been subject to increased interest from cellular network operators, not only as an extension to fixed broadband access. The interest is mainly about using the Wi-Fi technology as an extension, or alternative to cellular radio access network technologies to handle the always increasing wireless bandwidth demands. Cellular operators that are currently serving mobile users with, e.g., any of the 3GPP technologies, LTE, UMTS/WCDMA, or GSM, see Wi-Fi as a wireless technology that can provide good support in their regular cellular networks. The term “operator-controlled Wi-Fi” points to a Wi-Fi deployment that on some level is integrated with a cellular network operators existing network and where the 3GPP radio access networks and the Wi-Fi wireless access may even be connected to the same core network and provide the same services.
There is currently quite intense activity in the area of operator-controlled Wi-Fi in several standardization organizations. In 3GPP, activities to connect Wi-Fi access points to the 3GPP-specified core network is pursued, and in Wi-Fi alliance, WFA, activities related to certification of Wi-Fi products are undertaken, which to some extent also is driven from the need to make Wi-Fi a viable wireless technology for cellular operators to support high bandwidth offerings in their networks. The term Wi-Fi offload is commonly used and points towards that cellular network operators seek means to offload traffic from their cellular networks to Wi-Fi, e.g., in peak-traffic-hours and in situations when the cellular network for one reason or another needs to be off-loaded, e.g. to provide requested quality of service, maximize bandwidth or simply for coverage.